Wade Phillips poked around the edges trying to solve the quarterback mystery that has stumped the Broncos’ defense for three years. He went full Sherlock. And Phillips finally found a clue. Now he wants answers.

“Anybody think it’s interesting that the Colts, their symbol is a horseshoe, and their quarterback is named Luck?” Denver’s defensive coordinator wondered out loud. “Anybody notice that? Is that just a coincidence?”

Andrew Luck — the quarterback phenom who broke John Elway’s career touchdown record at Stanford, then pushed Peyton Manning out of Indianapolis — has directed a dominance over the Broncos that is unmatched since 2013. Denver is 37-11 over the past three years. But Luck and the Colts are 3-1 in that span against the Broncos.

“It’s a challenge for us,” Phillips said. After the Broncos butted heads with MVP Cam Newton and the Panthers last week, they will turn around for an equally tall task Sunday to face Luck and the Colts.

Luck last year ruined Denver’s then-undefeated season in Week 9, when he threw for 252 yards and two touchdowns to buckle the Broncos, 27-24. And he did it after the Broncos hit him so hard in the fourth quarter, they lacerated his kidney.

“I think all of my years going against him, the respect that he should get, I feel like I haven’t given it to him,” Broncos linebacker Von Miller said. “He’s one of the best quarterbacks in the league.”

What exactly does Luck do so well, especially against the Broncos? And how can they slow him down? In order of priority, here is Denver’s checklist against Luck:

1. The Line Read

Luck’s extrasensory perception when making a presnap read can break down defenders before even they know what they’ll be doing. He plays them like a marionette. Denver defensive end Billy Winn has a unique perspective on that ability. He played for the Colts last season, when Luck led Indy’s offense to the best performance of the season against the Broncos’ defense.

“He’s so smart reading defenses,” Winn said of Luck. “He’s able to process all this information, see where guys are lined up up front, see where the linebackers are pushed over, see where the safeties walked down. He’s able to do that in such a short period of time.”

Luck had the Colts at Denver’s 8-yard line last season on third-and-5 when the Broncos blitzed. They sent two extra players from the right side. But Luck had already read the rush. He calmly stepped back and flipped a short pass to running back Ahmad Bradshaw, who ran in for a score.

The key to staying ahead of Luck’s mind, Winn said, is to read him in return, finding clues on what the Colts are trying to do based on the personnel group they have in the game.

“The weapons they have, they can run any play. They can run dive, the slash play, anything outside, anything inside, under routes, over routes, deep balls,” Winn said. “You really have to read the keys.”

2. The Scramble

Luck can run with the best. He’s not as big as Ben Roethlisberger and he won’t run designed read-option plays like Cam Newton, but he is a hybrid. His frame, at 6-foot-4 and 240 pounds, is a chore to tackle, and he can move out of the pocket with confidence.

Miller, who brought down Newton for 2 1/2 sacks in the Super Bowl alone, has never sacked Luck in four games against him. That’s Miller’s most career games against an opposing quarterback without a sack, according to the NFL Network.

“I tackled him and he’s like, ‘Almost, Von. Good hit.’ That’s his character,” Miller said. “You’re looking for a quarterback (to say), ‘Man get off me.’ But he’s nice and says, ‘Good hit, man,’ when he just threw a 35-yard pass. It kind of has a reverse effect on you.”

The Denver defense last season hit Luck 11 times but sacked him only once. He’s a bear. Early in the first quarter last November, Miller rushed right up the middle and nailed Luck square in the ribs. But Luck still connected for a 28-yard pass to T.Y. Hilton.

“We talked about that,” Broncos linebacker DeMarcus Ware said. “You have to grab his right hand to make sure that he doesn’t throw the ball. There are certain techniques that you have have to take him down.”

3. The Comeback

In his career, Luck has led the Colts on 10 fourth-quarter comebacks and 14 game-winning drives — numbers that match Green Bay’s Aaron Rodgers. But Rodgers has played in more than twice as many games. Luck is perhaps the best in the league at bringing his team back.

Of course, that stat implies that the Colts are often losing in the fourth quarter.

Luck twice drove the Colts late against the Broncos last season. His touchdown pass to Bradshaw broke a tie early in the fourth quarter. And his five-play drive midway through the quarter, including three quick passes that covered 38 yards, led to Adam Vinatieri’s game-deciding field goal.

covers baseball and the Rockies and all sorts of sports. He started working at The Denver Post while in high school before graduating from the University of Colorado. Reach him at ngroke@denverpost.com